Using potentially bidentate ligands (-SC2H4NH2), we produced [2Fe-2S](+) species of different coordination geometries by fission of [4Fe-4S](2+) complexes. Even though the ligands are monodenlate in the cubane complexes, both mono- and bidentate complexes were observed in the [2Fe] fission products through self-assembly because of the high reactivity of the tricoordinate iron sites. The electronic structure of the [2Fe] species was probed using photoelectron spectroscopy and density functional calculations. It was found that tetracoordination significantly decreases the electron binding energies of the [2Fe] complexes, thus increasing the reducing capability of the [2Fe-2S](+) clusters.